Re: [PATCH RFC] scsi: wait sd probing in manual scan

From: Bart Van Assche
Date: Wed May 03 2017 - 14:15:18 EST

On Fri, 2017-04-28 at 15:48 +0800, Peng Tao wrote:
> We have a guest init programe trying to mount a device after doing scsi host scan
> at boot time. Occasionally it fails to find the device when mounting. After digging
> a bit, it seems the root cause is sd async_schedule probing.
> With async probing, there is no guarantee of device readiness when scsi host
> scan finishes. However, users do expect to have a valid way to make sure device
> is usable. Change scsi scan to wait sd probing in manual scan case so that we
> don't leave user with random device state when scsi host scan returns.
> Is this the right way to have such guarantee?

Hello Peng,

Please fix the guest init program such that it waits until the SCSI device
it needs is ready.